Furnace filter efficiency ratings, explained


Last month, we answered some frequently asked questions about air filters for your HVAC systems. This month, we are diving deeper into how you can choose the best filter for your system.

Firstly, the air filter you choose should fit the dimensions of your system.

Besides size, it all comes down to the level of filtration you want at a price you are comfortable with. You want a filter that will remove particulates that could harm your HVAC system, but you don’t necessarily just want the highest possible filtration. If your HVAC air filter is too strong, it could create unnecessary resistance in airflow, lower the performance of heating or air conditioning, and increase your energy costs.

These days, many brands indicate in fairly clear language what you can expect to be filtered out by each particular model, such as dust, pollen and fibers (thicker particulates) all the way to smoke and bacteria (smaller particulates). There is also an industry-standard rating level, but some brands use their own rating system, which can lead to confusion.

MERV is the HVAC industry’s standard rating system. It stands for “minimum efficiency reporting value” and rates filters from one to 20, with the higher numbers corresponding to more efficiency. Most residential filter systems would never need to go higher than 15 or 16, however.

The manufacturer 3M uses a system they call MPR (micro-particle performance rating), while The Home Depot uses FPR (filter performance rating) for its branded filters.

In general, you can look at three levels of filtration.

  •  HVAC filters that are around MERV 8, MPR 600 and FPR 5 will capture things like pollen, dust and dust mites.
  • Filters around MERV 11, MPR 1000 and FPR 7 will capture the previous particulates as well as smog, pet danger and sneeze particles.
  • At the higher end of residential use, filters around MERV 13, MPR 1500 to 1900 and FPR 10 will additionally trap smoke, bacteria and viruses.

Finding the right air filter can go a long way toward your HVAC system’s overall health. But for everything else, there’s Dominion Service Company and our 100% performance guarantee. If you have questions or need to make an appointment, call us at (800) 832-0758.